U.S. patent application number 17/421097 was filed with the patent office on 2022-04-07 for device and method for v2x communication.
The applicant listed for this patent is LG Electronics Inc.. Invention is credited to Jaeho HWANG, Woosuk KO.
Application Number | 20220107382 17/421097 |
Document ID | / |
Family ID | 1000006076246 |
Filed Date | 2022-04-07 |
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United States Patent
Application |
20220107382 |
Kind Code |
A1 |
HWANG; Jaeho ; et
al. |
April 7, 2022 |
DEVICE AND METHOD FOR V2X COMMUNICATION
Abstract
A method for obtaining, by a vehicle, information regarding its
own location through V2X communication is disclosed. Specifically,
the method for obtaining location information of a vehicle may
comprise the steps of: receiving a V2I message including location
information of a road side unit (RSU) from the RSU; receiving a V2X
message including reception time information related to a time when
the V2I message is received from each of a first surrounding
vehicle and a second surrounding vehicle; calculating a relative
position of the RSU relative to the current vehicle on the basis of
the reception time information and the time at which the current
vehicle received the V2I message; and acquiring the location of the
current vehicle on the basis of the relative location of the RSU
and the location information of the RSU.
Inventors: |
HWANG; Jaeho; (Seoul,
KR) ; KO; Woosuk; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG Electronics Inc. |
Seoul |
|
KR |
|
|
Family ID: |
1000006076246 |
Appl. No.: |
17/421097 |
Filed: |
January 10, 2019 |
PCT Filed: |
January 10, 2019 |
PCT NO: |
PCT/KR2019/000397 |
371 Date: |
July 7, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 4/12 20130101; G01S
5/0284 20130101; H04W 4/44 20180201; G01S 5/0072 20130101 |
International
Class: |
G01S 5/00 20060101
G01S005/00; G01S 5/02 20060101 G01S005/02; H04W 4/44 20060101
H04W004/44; H04W 4/12 20060101 H04W004/12 |
Claims
1. A method of obtaining position information of a current vehicle
by using V2X communication, comprising: receiving, from a road side
unit (RSU), a V2I message including position information of the
RSU; receiving, from each of a first surrounding vehicle and a
second surrounding vehicle, a V2X message including reception time
information related to time when the V2I message is received;
calculating a relative position of the RSU based on the current
vehicle, based on the reception time information and time when the
current vehicle receives the V2I message; and obtaining a position
of the current vehicle based on the relative position of the RSU
and the position information of the RSU.
2. The method of claim 1, wherein the position information of the
RSU includes coordinates of the RSU, and wherein the position of
the current vehicle is obtained by subtracting the relative
position of the RSU from the coordinates of the RSU.
3. The method of claim 1, wherein the relative position of the RSU
is calculated using a first difference value between time when the
first surrounding vehicle receives the V2I message and the time
when the current vehicle receives the V2I message and a second
difference value between time when the second surrounding vehicle
receives the V2I message and the time when the current vehicle
receives the V2I message.
4. The method of claim 1, wherein the reception time information
includes time interval information from time when the first
surrounding vehicle or the second surrounding vehicle receives the
V2I message to time when the first surrounding vehicle or the
second surrounding vehicle transmits the V2X message.
5. The method of claim 1, further comprising: generating a
cooperative awareness (CA) message or a collective perception (CP)
message including the obtained position of the current vehicle.
6. A V2X communication apparatus of a vehicle, comprising: a memory
storing data; a communication unit transmitting and receiving radio
signals including a V2I message; and a processor configured to
control the memory and the communication unit, wherein the
processor is configured to: receive, from a road side unit (RSU), a
V2I message including position information of the RSU, receive,
from each of a first surrounding vehicle and a second surrounding
vehicle, a V2X message including reception time information related
to time when the V2I message is received, calculate a relative
position of the RSU based on the current vehicle, based on the
reception time information and time when the current vehicle
receives the V2I message, and obtain a position of the current
vehicle based on the relative position of the RSU and the position
information of the RSU.
7. The V2X communication apparatus of claim 6, wherein the position
information of the RSU includes coordinates of the RSU, and wherein
the position of the current vehicle is obtained by subtracting the
relative position of the RSU from the coordinates of the RSU.
8. The V2X communication apparatus of claim 6, wherein the relative
position of the RSU is calculated using a first difference value
between time when the first surrounding vehicle receives the V2I
message and the time when the current vehicle receives the V2I
message and a second difference value between time when the second
surrounding vehicle receives the V2I message and the time when the
current vehicle receives the V2I message.
9. The V2X communication apparatus of claim 6, wherein the
reception time information includes time interval information from
time when the first surrounding vehicle or the second surrounding
vehicle receives the V2I message to time when the first surrounding
vehicle or the second surrounding vehicle transmits the V2X
message.
10. The V2X communication apparatus of claim 6, wherein the
processor is configured to generate a cooperative awareness (CA)
message or a collective perception (CP) message including the
obtained position of the current vehicle.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to an apparatus and method
for vehicle to everything (V2X) communication and, more
particularly, to a method of obtaining position information of a
vehicle through V2X communication.
BACKGROUND ART
[0002] Recently, a vehicle becomes a product of a complex
industrial technology in which electrical, electronic and
communication technologies have been converged out of mechanical
engineering. In this respect, a vehicle is also called a smart car.
The smart car provides various customized mobile services in
addition to conventional vehicle technologies, such as traffic
safety/congestion solution, by connecting drivers, vehicles, and
transportation infrastructure. Such connectivity may be implemented
using a vehicle to everything (V2X) communication technology.
DISCLOSURE
Technical Problem
[0003] Conventional automobiles use a GPS system using satellites
to check their positions. Since the GPS system needs to receive
signals from at least three satellites, it is greatly affected by
the surrounding environment. Position information cannot be used in
indoor environments where GPS signals are not received, such as
tunnels or underground parking lots. In addition, even when the
weather is bad or when driving in an urban area with many
buildings, position recognition performance is attenuated.
[0004] The position recognition technology using inertial
navigation is used as a compensation technology in areas where GPS
does not operate. However, this technology is a system in which
position errors may be accumulated, and may rather deteriorate the
position recognition performance. There is a need to develop a
technology to improve the above problems and improve the position
recognition performance of the V2I device in an environment where
GPS signals are not normally received.
Technical Solution
[0005] In order to accomplish the object, the present disclosure
proposes a method and apparatus for V2X communication.
[0006] A method of obtaining position information of a vehicle
through V2X communication according to an embodiment of the present
disclosure may include receiving, from a road side unit (RSU), a
V2I message including position information of the RSU, receiving,
from each of a first surrounding vehicle and a second surrounding
vehicle, a V2X message including reception time information related
to the time when receiving the V2I message, calculating a relative
position of the RSU based on the current vehicle, based on the
reception time information and the time when the current vehicle
receives the V2I message, and obtaining a position of the current
vehicle based on the relative position of the RSU and the position
information of the RSU.
[0007] As an embodiment, the position information of the RSU may
include coordinates of the RSU, and the position of the current
vehicle may be obtained by subtracting the relative position of the
RSU from the coordinates of the RSU.
[0008] As an embodiment, the relative position of the RSU may be
calculated using a first difference value between the time when the
first surrounding vehicle receives the V2I message and the time
when the current vehicle receives the V2I message and a second
difference value between the time when the second surrounding
vehicle receives the V2I message and the time when the current
vehicle receives the V2I message.
[0009] As an embodiment, the reception time information may include
time interval information from the time when the first surrounding
vehicle or the second surrounding vehicle receives the V2I message
to the time when the first surrounding vehicle or the second
surrounding vehicle transmits the V2X message.
[0010] As an embodiment, the method may further include generating
a cooperative awareness (CA) message or a collective perception
(CP) message including the obtained position of the current
vehicle.
[0011] A V2X communication apparatus for obtaining position
information of a vehicle through V2I communication according to
another embodiment of the present disclosure includes a memory
storing data, a communication unit transmitting and receiving radio
signals including a V2I message, and a processor configured to
control the memory and the communication unit. The processor may be
configured to receive, from a road side unit (RSU), a V2I message
including position information of the RSU, receive, from each of a
first surrounding vehicle and a second surrounding vehicle, a V2X
message including reception time information related to the time
when the V2I message is received, calculate a relative position of
the RSU based on the current vehicle, based on the reception time
information and the time when the current vehicle receives the V2I
message, and obtain a position of the current vehicle based on the
relative position of the RSU and the position information of the
RSU.
[0012] As an embodiment, the position information of the RSU may
include coordinates of the RSU, and wherein the position of the
current vehicle may be obtained by subtracting the relative
position of the RSU from the coordinates of the RSU.
[0013] As an embodiment, the relative position of the RSU may be
calculated using a first difference value between the time when the
first surrounding vehicle receives the V2I message and the time
when the current vehicle receives the V2I message and a second
difference value between the time when the second surrounding
vehicle receives the V2I message and the time when the current
vehicle receives the V2I message.
[0014] As an embodiment, the reception time information may include
time interval information from the time when the first surrounding
vehicle or the second surrounding vehicle receives the V2I message
to the time when the first surrounding vehicle or the second
surrounding vehicle transmits the V2X message.
[0015] As an embodiment, the processor may be configured to
generate a cooperative awareness (CA) message or a collective
perception (CP) message including the obtained position of the
current vehicle.
Advantageous Effects
[0016] According to an embodiment of the present disclosure,
accurate position information of a vehicle can be effectively
obtained in an environment in which a GPS reception ratio is not
good.
[0017] Furthermore, according to an embodiment of the present
disclosure, the position of a vehicle can be accurately obtained
using a road side unit (RSU) and surrounding vehicles in an
environment in which time synchronization between vehicles is not
performed.
DESCRIPTION OF DRAWINGS
[0018] The accompany drawings which are included for further
understanding of the disclosure and included in this disclosure and
which form part of the disclosure illustrate embodiments of the
disclosure along with the detailed description that describes the
principle of the disclosure.
[0019] FIG. 1 illustrates exemplary architecture of a V2X
communication device according to an embodiment of the
disclosure.
[0020] FIG. 2 illustrates a method of processing a V2X message
according to an embodiment of the disclosure.
[0021] FIG. 3 illustrates architecture of a V2X communication
apparatus which provides infrastructure services according to an
embodiment of the present disclosure.
[0022] FIG. 4 is a diagram for describing a method of recognizing
position information of a vehicle according to a conventional
technology.
[0023] FIG. 5 is a diagram for describing a method of recognizing
position information of a vehicle according to an embodiment of the
present disclosure.
[0024] FIG. 6 is a diagram for describing a method of obtaining an
absolute position of a vehicle according to an embodiment of the
present disclosure.
[0025] FIG. 7 is a diagram illustrating a method of obtaining the
position of an RSU according to an embodiment of the present
disclosure.
[0026] FIG. 8 is a diagram for describing a method of obtaining a
relative position of an RSU according to an embodiment of the
present disclosure.
[0027] FIGS. 9 and 10 are diagrams for describing a problem which
may occur if time synchronization is not presupposed.
[0028] FIG. 11 is a diagram for describing a method of obtaining a
relative position of an RSU according to an embodiment of the
present disclosure.
[0029] FIG. 12 is a diagram illustrating the structure of a data
frame of a V2I message transmitted by a road side unit (RSU)
according to an embodiment of the present disclosure.
[0030] FIG. 13 is a diagram illustrating the structure of a data
frame of a cooperative awareness message (CAM) according to an
embodiment of the present disclosure.
[0031] FIG. 14 is a diagram illustrating the structure of a data
frame of a collective perception message (CPS) according to an
embodiment of the present disclosure.
[0032] FIG. 15 is a flowchart illustrating a procedure of obtaining
and propagating position information of a vehicle that provides a
CP service according to an embodiment of the present
disclosure.
[0033] FIG. 16 is a flowchart illustrating a procedure of obtaining
and propagating position information of a vehicle that provides a
CA service according to an embodiment of the present
disclosure.
[0034] FIG. 17 is a diagram for describing a form in which a V2I
message is transmitted according to an embodiment of the present
disclosure.
[0035] FIG. 18 is a flowchart illustrating a method of generating a
V2I message according to an embodiment of the present
disclosure.
[0036] FIG. 19 is a flowchart illustrating a method of generating a
CAM message according to an embodiment of the present
disclosure.
[0037] FIG. 20 is a flowchart illustrating a method of obtaining
position information according to an embodiment of the present
disclosure.
[0038] FIG. 21 illustrates a configuration of a V2X communication
apparatus according to an embodiment of the present disclosure.
[0039] FIG. 22 is a flowchart illustrating a method of obtaining,
by a V2X communication apparatus, position information according to
an embodiment of the present disclosure.
BEST MODE
[0040] Preferred embodiments of the disclosure will be described in
detail with reference to the accompanying drawings. The following
detailed description with reference to the accompanying drawings is
to illustrate preferred embodiments of the disclosure rather than
illustrate only embodiments that can be implemented according to
embodiments of the disclosure. The following detailed description
includes details in order to provide the full understanding of the
disclosure, but the disclosure does not require all of these
details. The embodiments described below need not be separately
used. A plurality of embodiments or all embodiments may be together
used, and specific embodiments may be used in combination with each
other.
[0041] Most of the terms used in this disclosure are selected from
common ones widely used in the corresponding field, but some terms
are arbitrarily selected by the applicant and the meaning thereof
will be described in detail in the following description as
necessary. Therefore, the disclosure should be understood based on
the intended meanings of the terms rather than the simple names or
meanings of the terms.
[0042] The disclosure relates to a V2X communication device. The
V2X communication device is included in an intelligent transport
system (ITS), and may perform some of or all the functions of the
ITS system. The V2X communication device may perform communication
between a vehicle and a vehicle, a vehicle and infrastructure, a
vehicle and a bicycle, or with a mobile device. In one embodiment
the V2X communication device may correspond to the on board unit
(OBU) of a vehicle or may be included in an OBU. The OBU may be
referred to as an on board equipment (OBE). The V2X communication
device may correspond to a road side unit (RSU) of infrastructure
or may be included in an RSU. The RSU may be referred to as
roadside equipment (RSE). Alternatively, the V2X communication
device may correspond to an ITS station or may be included in an
ITS station. All of given OBU, RSU and mobile equipment that
perform V2X communication may be referred to as ITS stations.
Alternatively, the V2X communication device may correspond to a
wireless access in vehicular (WAVE) apparatus or may be included in
a WAVE apparatus. The V2X communication device may be abbreviated
as a V2X apparatus.
[0043] FIG. 1 is a view illustrating an exemplary architecture of
an V2X communication device according to an embodiment of the
disclosure. FIG. 1 may be an exemplary architecture of a V2X
communication device that may be implemented based on, for example,
the reference architecture of an ITS station compliant with the EU
standard.
[0044] Application layer: The application layer may implement and
support various use cases. For example, an application may provide
road safety, efficient traffic information, and other application
information.
[0045] Facilities layer: The facilities layer may support effective
implementation of various usage examples defined in the application
layer.
[0046] This facilities layer may basically support the same or
similar functions as the upper three layers of an OSI model. In
addition, facilities for the V2X communication device may be
provided. For example, the facilities layer may provide facilities
such as application support, information support, and
session/communication support. Here, the facilities refer to a
component that provides functionality, information, and data. The
three facilities proposed as an example will be described as
follows.
[0047] The application support facility refers to a facility that
supports a basic application set (or message set). In the case of
the V2X communication device of FIG. 1, the facilities layer may
support V2X messages/ITS messages, for example, a periodic message
such as CAM or an event message such as Decentralized Environmental
Notification Messages (DENM). The facilities layer may also
support, for example, CPM messages.
[0048] The information support facility may be a facility that
provides common data information or database used for a basic
application set (or message set), and may be, for example, a Local
Dynamic Map (LDM).
[0049] The session/communication support facility is a facility
that provides services for communication and session management,
and may be an addressing mode, a session support and the like.
[0050] As described above, the facilities layer supports the
application set (or message set) as one of main functions thereof.
That is, the facilities layer performs a role of generating a
message set (or message) based on information to be transmitted or
a service to be provided by the application layer. The generated
message may be referred to as an V2X message/ITS message, which
will be described in detail below with reference to the
accompanying drawings.
[0051] Access layer: The access layer may transmit the message/data
received at the upper layers through a physical channel. For
example, the access layer may perform/support data communication,
based on an IEEE 802.11 and/or 802.11p standards-based
communication technology, an ITS-G5 wireless communication
technology based on a physical transmission technology of the IEEE
802.11 and/or 802.11p standards, a 2G/3G/4G (LTE)/5G wireless
cellular communication technology including satellite/broadband
wireless mobile communication, a broadband terrestrial digital
broadcasting technology such as DVB-T/T2/ATSC, a GPS technology,
and an IEEE 1609 WAVE technology.
[0052] Network and Transport Layer: The network/transport layer may
configure a network for vehicle communication between
homogenous/heterogeneous networks, by using various transport
protocols and network protocols.
[0053] The transport layer is a connection layer between services
provided by the upper layers (session layer, presentation layer,
and application layer) and the lower layers (network layer, data
link layer, and physical layer). The transport layer may manage the
transmitted data to exactly arrive at a destination. At the
transmitting side, the transport layer may process the data into
packets of an appropriate size for efficient data transmission, and
at the receiving side, the transport layer may perform processing
to recover the received packets to the original file. In an
embodiment, protocols such as Transmission Control Protocol (TCP),
User Datagram Protocol (UDP), and Basic Transport Protocol (BTP)
may be used as a transport protocol.
[0054] The network layer may manage the logical address, and may
determine the delivery path of the packet. The network layer may
receive the packet generated in the transport layer, and may add
the logical address of the destination to a network layer header.
In an embodiment, the packet path may be considered for
unicast/broadcast between vehicles, between vehicles and fixed
stations, and between fixed stations. In an embodiment,
geo-networking, IPv6 networking with mobility support, and IPv6
over geo-networking may be considered as the networking
protocol.
[0055] The exemplary architecture of V2X communication device may
further include a management layer and a security layer.
[0056] FIG. 2 is a view illustrating a method of processing a V2X
message according to an embodiment of the disclosure.
[0057] As described above, the application layer or the facilities
layer may generate a V2X message. For example, a CAM, a DENM, or a
CPM message may be generated as the V2X message.
[0058] The transport layer may generate a BTP packet, and the
network layer may encapsulate the BTP packet to generate a
GeoNetworking packet. The GeoNetworking packet may be encapsulated
into an LLC packet. In the embodiment of FIG. 2, the data may
include a message set, and the message set may become a basic
safety message.
[0059] BTP is a protocol for transmitting the V2X message generated
in a facilities layer to a lower layer. A BTP header includes A
type and B type. The A type BTP header may include a
destination/destination port and a source port, which are necessary
for transmission/reception in interactive packet transmission. The
B type header may include destination port and destination port
information necessary for transmission in non-interactive packet
transmission. A description of fields/information included in the
header is as follows.
[0060] Destination Port: The destination port identifies a facility
entity corresponding to the destination of the data (BTP-PDU)
included in the BTP packet.
[0061] Source Port: As a field generated in the case of the BTP-A
type, the sound port indicates the port of the protocol entity of
the facilities layer at a source to which the corresponding packet
is transmitted. This field may have a size of 16 bits.
[0062] Destination Port Info: As a field generated in the case of
the BTP-B type. The destination port info may provide additional
information when the destination port is the most well-known port.
This field may have a size of 16 bits.
[0063] The GeoNetworking packet includes a basic header and a
common header according to the protocol of the network layer, and
selectively includes an extension header according to the geo
networking mode. The GeoNetworking header will be again described
below.
[0064] An LLC header is added to the GeoNetworking packet to
generate an LLC packet. The LLC header provides a function of
distinguishing and transmitting IP data and GeoNetworking data. The
IP data and the GeoNetworking data may be distinguished by
Ethertype of SNAP. In an embodiment, when IP data is transmitted,
the Ether type may be set to 0x86DD and included in the LLC header.
In an embodiment, when GeoNetworking data is transmitted, the Ether
type may be set to 0x86DC and included in the LLC header. A
receiver may check the Ethertype field of the LLC packet header,
and may forward and process the packet to the IP data path or the
GeoNetworking path according to the value of the Ethertype field of
the LLC packet header.
[0065] FIG. 3 is a view illustrating an exemplary architecture of a
V2X communication device providing a CP service according to an
embodiment of the disclosure.
[0066] The V2X communication device may provide various services
for traffic safety and efficiency. One of the services may be a
Cooperative Awareness (CA) service. The Cooperative Awareness in
road traffic means that road users and roadside infrastructures can
know mutual positions, dynamics and attributes. Here, the road
users may be all kinds of users on a road or near a road, which act
as traffic safety and control, such as a vehicle, a truck, a
motorcycle, a bicycle or a pedestrian, and the roadside
infrastructures may be equipment including a road sign, a traffic
light or a barrier and an entrance.
[0067] This awareness of each other becomes basics of many road
safety and traffic efficiency applications. This can be performed
by regular exchange of information between road users at vehicle to
vehicle (V2V), vehicle to infrastructure (V2I), infrastructure to
vehicle (12V) or everything to everything (X2X) which are based on
a wireless network called a V2X network.
[0068] On this other hand, the cooperative safety and traffic
efficiency applications require the V2X communication device to
develop situational awareness that includes the presence and
behavior of road users around the V2X communication device. For
example, the V2X communication device may develop situational
awareness through communication with its own sensors and other V2X
communication devices.
[0069] An infrastructure service may designate whether the V2I
communication device of the RSU may notify other V2X communication
devices about positions, dynamics and characteristics of the
detected neighboring road users and other objects. For example, the
infrastructure service may share this information with other V2X
communication devices through transmission of an indoor positioning
message (IPM). This infrastructure service may be an optional
facility for all types of V2X communication devices (vehicle V2X
communication device, RSU V2X communication device, personal V2X
communication device, etc.) participating in road traffic.
[0070] V2I technology is about communication technology between an
infrastructure and a vehicle among V2X. In the present disclosure,
the infrastructure represents a fixed communication device that
performs V2X communication. For example, it may be a traffic light
or a communication device installed at an intersection. The
infrastructure may be referred to as a road side unit (RSU). The
V2I technology includes "Traffic Light Maneuver" technology that
informs driving availability information such a traffic light
through the RSU connected to the network, "Toad and Lane Topology"
technology that informs road conditions and lane composition,
"Infrastructure to Vehicle information" technology that informs the
vehicle of road condition information, "Traffic Light control"
technology that manages signals, etc.
[0071] As shown in FIG. 3, the ITS system provides a system
corresponding technology through the infrastructure service in a
facility layer as shown in the drawing below. That is, the
infrastructure service may be a facility layer entity. For example,
the infrastructure service may be a part of the application support
domain of the facility layer. FIG. 3 exemplarily illustrates the
infrastructure service in V2X communication device architecture and
a logical interface for other layers and a potential logical
interface for entities in the facility layer.
[0072] When transmitting, the facility layer generates/encodes a
message according to an operation requested by an application, and
manages the transmission of the message. When receiving, the
facility layer decodes the message received through the NF-SAP at
the network and transport (N&T: Network & Transport) layer
and transmits the received message to the application layer.
Information by message management is connected to the management
layer through MF-SAP, and is connected to the security layer
through SF-SAP for message security.
[0073] In the present disclosure, a transmitting V2X communication
apparatus may also be denoted as a transmission V2X communication
device, a transmission V2X communication apparatus, a host V2X
communication apparatus, etc.
[0074] A conventional vehicle uses a GPS using satellites in order
to identify its own position. The GPS is greatly influenced by
surrounding environments because it needs to receive signals from
at least three satellites. Location information cannot be used in
an indoor environment in which a GPS signal is not received, such
as a tunnel or an underground parking lot. Furthermore, when the
weather is not good or when a vehicle operates in a downtown area
including many buildings, position recognition performance is
attenuated.
[0075] In a conventional position recognition technology, inertial
navigation is used as a compensation technology in an area in which
a GPS does not operate. However, the corresponding technology is a
system in which position errors may be accumulated, and may
deteriorate position recognition performance. Accordingly, the
present disclosure proposes a method of improving such a problem
and effectively obtaining position information of a vehicle through
V2I communication in an environment in which a GPS signal is not
received normally.
[0076] In particular, the present disclosure proposes a method of
obtaining accurate position information of a vehicle by using one
RSU. First, a conventional position recognition technology using
three or more RSUs is described below with reference to a drawing
below.
[0077] FIG. 4 is a diagram for describing a method of recognizing
position information of a vehicle according to a conventional
technology.
[0078] Referring to FIG. 4, in a conventional position measurement
technology, three or more RSUs at already known fixed positions may
be used to obtain the position of a vehicle. In this case, in order
to obtain the position of an ego vehicle 4010, a propagation time
or received signal strength indication (RSSI) of a signal may be
used. However, positioning using the RSSI has a problem in that it
is not suitable for precise position measurement because an error
is great.
[0079] Accordingly, in the conventional position measurement
technology, a propagation time of a signal having high precision
compared to RSSI is used. If RSUs have been synchronized, a
position may be measured in one way by using a time difference of
arrival (TDoA) of a signal. If TDoA is used on the premise of time
synchronization between RSUs, accurate positions of a plurality of
vehicles can be estimated at a time. In contrast, if time
synchronization has not been performed, a position including the
distance between an RSU and a vehicle may be measured using a time
of arrival (ToA) of a signal. However, this method has
disadvantages in that position measurement in two ways is necessary
and the position of one vehicle cannot be measured at a time.
[0080] When traffic safety and efficiency are considered, in order
to be substantially used in a vehicle environment, a position needs
to be identified at a time in one way and positions of a plurality
of vehicles needs to be measured at a time. The TDoA method may be
a method most suitable for a vehicle system, but the method also
has a disadvantage in that RSUs must be synchronized and has a
problem in that three or more RSUs in which a vehicle is placed in
a line of sight (LoS) situation must be present. However, in a road
environment positioned between buildings, there is a limit that the
RSUs are installed to guarantee three or more LOS environments. In
this case, the LoS indicates a distance or area where a straight
line can be reached through a radio wave or the human eye.
[0081] Accordingly, in order to solve this problem, the present
disclosure proposes a method of recognizing the position of a
vehicle by using one RSU. As an embodiment, the method proposed in
the present disclosure is a technology suitable for a vehicle
driving environment, and may use one RSU and three or more
vehicles. This is described with reference to a drawing below.
[0082] FIG. 5 is a diagram for describing a method of recognizing
position information of a vehicle according to an embodiment of the
present disclosure.
[0083] Referring to FIG. 5, an RSU 5040 transmits, to the
surroundings, a V2I message including information on its fixed
position. Vehicles that are driving around the RSU 5040 may receive
the V2I message. In this case, each of the receivers (i.e., the
vehicle) may notify a surrounding vehicle of the time when the V2I
message was received through a cooperative awareness message (CAM)
(or a collective perception message (CMP). Thereafter, an ego
vehicle (or current vehicle) 5020 may obtain (or measure or
estimate) a relative position of the RSU between the ego vehicle
5020 and each of the surrounding vehicles 5030 and 5040 by using
its measured V2I message reception time and V2I message reception
times of the surrounding vehicles received through the surrounding
vehicles 5030 and 5040. In this case, the relative position of the
RSU may be obtained using a difference between an RSU signal and a
received signal.
[0084] In an embodiment of the present disclosure, a calculation
method described hereinafter may be used to estimate an actual
position value of a vehicle.
[0085] FIG. 6 is a diagram for describing a method of obtaining an
absolute position of a vehicle according to an embodiment of the
present disclosure.
[0086] Referring to FIG. 6, an ego vehicle 6020 first sets its
temporary position (or relative position) as [0,0]. Furthermore,
the ego vehicle 6020 may obtain a relative position of each of an
RV1 vehicle 6030 and an RV2 vehicle 6040 based on the ego vehicle
6020 by using a sensor mounted thereon. As an embodiment, in the
coordinates of each of the RV1 vehicle 6030 and the RV2 vehicle
6040, a Y axis may be set to be directed toward a north direction.
As illustrated in FIG. 6, [-10, 500] values may be obtained as a
relative position of the RV1 vehicle 6030. [400, 10] values may be
obtained as a relative position of the RV2 vehicle 6040.
[0087] Thereafter, the ego vehicle 6020 receives a V2I message from
an RSU 6010. The V2I message may include absolute position (or
absolute coordinates) information of the RSU. For example, the
absolute position of the RSU may be a coordinate value of a GPS,
such as [34.11'.23'', 20.44'.26''], as illustrated in FIG. 6.
[0088] Furthermore, the ego vehicle 6020 may calculate a relative
position of the RSU 6010 by using signals received from the RSU
6010, the RV1 vehicle 6030, and the RV2 vehicle 6040. As
illustrated in FIG. 6, the relative position of the RSU 6010 may be
calculated as [1000, 1200].
[0089] Finally, the ego vehicle 6020 may calculate an absolute
position of the ego vehicle 6020 by using the calculated relative
position of the RSU 6010 and the absolute position of the RSU 6010
obtained from the V2I message. In this case, Equation 1 below may
be used.
Pos e .times. s .times. t .times. i .times. m .times. a .times. t
.times. e .times. d E .times. V = P .times. o .times. s r .times. e
.times. a .times. l R .times. S .times. U - P .times. o .times. s r
.times. e .times. l .times. a .times. t .times. i .times. v .times.
e R .times. S .times. U [ Equation .times. .times. 1 ]
##EQU00001##
[0090] In Equation 1, Pos.sub.estimated.sup.EV indicates the
absolute position (or calculated position) of the ego vehicle 6020,
Pos.sub.real.sup.RSU indicates the absolute position of the RSU
6010, and Pos.sub.relative.sup.RSU indicates the relative position
of the RSU 6010.
[0091] The absolute position of the ego vehicle 6020 may be
obtained by subtracting a relative RSU value (the relative position
of the RSU 6010) from an actual RSU value (i.e., the absolute
position of the RSU 6010).
[0092] Furthermore, the absolute position of each surrounding
vehicle (the RV1 vehicle 6030, the RV2 vehicle 6040) may be
estimated using the estimated absolute value of the ego vehicle
6020 by using Equation 1. In this case, Equation 2 and Equation 3
below may be used.
P .times. o .times. s e .times. s .times. t .times. i .times. m
.times. a .times. t .times. e .times. d R .times. V .times. 1 = P
.times. o .times. s e .times. s .times. t .times. i .times. m
.times. a .times. t .times. i .times. e .times. d E .times. V + P
.times. o .times. s r .times. e .times. l .times. a .times. t
.times. i .times. v .times. e R .times. V .times. 1 [ Equation
.times. .times. 2 ] Po .times. s e .times. s .times. t .times. i
.times. m .times. a .times. t .times. e .times. d R .times. V
.times. 2 = P .times. o .times. s e .times. s .times. t .times. i
.times. m .times. a .times. t .times. i .times. e .times. d E
.times. V + P .times. o .times. s r .times. e .times. l .times. a
.times. t .times. i .times. v .times. e R .times. V .times. 2 [
Equation .times. .times. 3 ] ##EQU00002##
[0093] In Equation 2, Pos.sub.estimated.sup.RV1 indicates the
absolute position (or calculated position) of the RV1 vehicle 6030,
and Pos.sub.relative.sup.RV1 indicates the relative position of the
RV1 vehicle 6030. Furthermore, in Equation 3,
Pos.sub.estimated.sup.RV2 indicates the absolute position (or
calculated position) of the RV2 vehicle 6040, and
Pos.sub.relative.sup.RV2 indicates the relative position of the RV2
vehicle 6040.
[0094] In an embodiment, the position information of the ego
vehicle 6020 or the surrounding vehicles (the RV1 vehicle 6030 and
the RV2 vehicle 6040) obtained using Equations 1 to 3 may be
included in a CAM message or a CPM message.
[0095] Hereinafter, a method of obtaining a relative position (or
may also be denoted as a predicted value or a predicted position)
of an RSU is described in detail.
[0096] FIG. 7 is a diagram illustrating a method of obtaining the
position of an RSU according to an embodiment of the present
disclosure.
[0097] Referring to FIG. 7, in an embodiment of the present
disclosure, a procedure for transmitting and receiving signals
according to the TDoA method by using one RSU 7010 may be
performed. First, the RSU 7010 transmits a V2I message at a time
t1. Each of the vehicles (i.e., an RV1 vehicle 7020, an RV2 vehicle
7030, and an ego vehicle 7040 (or current vehicle)) receives the
V2I message transmitted by the RSU 7010.
[0098] In FIG. 7, a case where distances from the RSU 7010 to the
vehicles (i.e., the RV1 vehicle 7020, the RV2 vehicle 7030, and the
ego vehicle 7040 (or the current vehicle)) are the same is assumed.
If the distances from the RSU 7010 are the same, the RV1 vehicle
7020, the RV2 vehicle 7030, and the ego vehicle 7040 may receive
the V2I message at the same times t1-1, t1-2, and t1-3. Thereafter,
when transmitting its message (e.g., CAM or CPM) in its message
transmission period, each of the RV1 vehicle 7020 and the RV2
vehicle 7030 may notify the ego vehicle 7040 of the time when the
V2I message was received. That is, the ego vehicle 7040 may receive
a first V2X message from the RV1 vehicle 7020 at a time t2-3, and
may receive a second V2X message from the RV2 vehicle 7030 at a
time t3-3. In this case, the first V2X message includes information
on the time when the RV1 vehicle 7020 received the V2I message. The
second V2X message may include information on the time when the RV2
vehicle 7030 received the V2I message. As an embodiment, the first
V2X message may be a CAM message or a CPM message.
[0099] Accordingly, the ego vehicle 7040 may recognize the V2I
message reception times of all the vehicles after the time t3-3,
and may calculate relative position coordinates of the RSU
7010.
[0100] In order to apply the TDoA method, each of the vehicles may
compare differences between signals received from the RSU 7010. In
FIG. 7, it has been assumed that the vehicles are disposed at the
same distance from the RSU 7010. Accordingly, as in Equation 4
below, a difference between signal reception times of the two
vehicles transmitted by the RSU 7010 may have a value of 0.
.DELTA. RV .times. .times. 1 - EV = t 1 - 1 - t 1 - 3 = 0 .times.
.times. .DELTA. RV .times. .times. 2 - EV = t 1 - 2 - t 1 - 3 = 0 [
Equation .times. .times. 4 ] ##EQU00003##
[0101] In Equation 4, .DELTA..sub.RV1-EV indicates a difference
between the times when the RV1 vehicle 7020 and the ego vehicle
7040 receive the V2I message. .DELTA..sub.RV2-EV indicates a
difference the times when the RV2 vehicle 7030 and the ego vehicle
7040 receive the V2I message. Furthermore, t.sub.1-1, t.sub.1-2,
and t.sub.1-3 indicate the times when the RV1 vehicle 7020 the
vehicle, the RV2 vehicle 7030, and the ego vehicle 7040 receive
signal transmitted by the RSU 7010, respectively.
[0102] Referring to Equation 4, a difference between the time when
each of the surrounding vehicles (i.e., the RV1 vehicle 7020 and
the RV2 vehicle 7030) received the V2I message and the time when
the ego vehicle 7040 received the V2I message may be calculated. A
relative position (or predicted value or predicted position) of the
RSU 7010 based on the ego vehicle 7040 may be obtained using the
difference.
[0103] FIG. 8 is a diagram for describing a method of obtaining a
relative position of an RSU according to an embodiment of the
present disclosure.
[0104] Referring to FIG. 8, a case where distances from an RSU 8010
to surrounding vehicles (i.e., an RV1 vehicle 8020, an RV2 vehicle
8040, and an ego vehicle 8030 (or a current vehicle)) are the same
is assumed. If a difference between times when the RV1 vehicle 8020
and the ego vehicle 8030 receive a V2I message is obtained using
the method described with reference to FIG. 7, as in the TDoA
method, a hyperbola, such as that illustrated in FIG. 8, may be
illustrated between the RV1 vehicle 8020 and the ego vehicle 8030.
In the present embodiment, since there is no difference between
times when the RV1 vehicle 8020 and the ego vehicle 8030 receive a
V2I signal, the distance between the RSU 8010 and the two vehicles
may be the same. That is, the RSU 8010 may be disposed on a dotted
line 8050 illustrated between the RV1 vehicle 8020 and the ego
vehicle 8030.
[0105] Likewise, even in the case of a difference between times
when the RV2 vehicle 8040 and the ego vehicle 8030 received the V2I
message, a position where the RSU 8010 may be present may be
represented using a hyperbola. In the present embodiment, since
there is no difference between the times when the RV2 vehicle 8040
and the ego vehicle 8030 receive the V2I signal, the RSU 8010 may
be disposed on a dotted line 8060 illustrated between the RV2
vehicle 8040 and the ego vehicle 8030.
[0106] Furthermore, an intersection point of a straight line or a
curve may be obtained based on the aforementioned two time
differences. The intersection point may be determined (or obtained)
as a relative position of the RSU 8010.
[0107] In a position recognition method using the aforementioned
TDoA, times between surrounding vehicles (e.g., EV, RV1, and RV2)
need to be synchronized. If time synchronization between the
vehicles has not been performed, although the surrounding vehicles
receive an RSU signal at the same time, the vehicles may operate as
if they receive the RSU signal at different times due to a time
synchronization error. In other words, if times between a current
vehicle and surrounding vehicles RV1 and RV2 are not synchronized,
an error may occur in position measurement. An error which may
occur is described with reference to drawings below.
[0108] FIGS. 9 and 10 are diagrams for describing a problem which
may occur if time synchronization is not presupposed.
[0109] Referring to FIGS. 9 and 10, a case where distances from an
RSU 9010 to surrounding vehicles (i.e., an RV1 vehicle 9020, an RV2
vehicle 9030, and an ego vehicle 9040 (or a current vehicle)) are
the same is assumed. Furthermore, a case where time of the RV1
vehicle 9020 is ahead of a reference time (i.e., time of the RSU
9010) by .alpha._RV1, time of the RV2 vehicle 9030 is behind the
reference time by .alpha._RV2, and time of the ego vehicle (or the
current vehicle) 9040 is ahead of the reference time by .alpha._EV
is assumed.
[0110] As in the embodiments described with reference to FIGS. 7
and 8, although the times when the signal (i.e., the V2I message)
of the RSU 9010is is actually received are the same, if times
between the surrounding vehicles 9020 and 9030 and the ego vehicle
9040 are not synchronized, it may be recognized that the signal of
the RSU 9010 was received at different times.
[0111] That is, as in a conventional technology, although the RV1
vehicle 9020 receives the signal at a time t1-1, the RV1 vehicle
9020 may notify surroundings that the signal of the RSU 9010 is
received early because time set in the RV1 vehicle is ahead of the
reference time by .alpha._RV1. In contrast, the RV2 vehicle 9030
receives the signal of the RSU 9010 at the same time as the RV1
vehicle 9020, but the RV2 vehicle 9030 may notify surroundings of a
time added by a time synchronization error (i.e., .alpha._RV2) of
the RV2 vehicle 9030.
[0112] Equation 5 below indicates V2I signal reception times t1-1
and t1-2 of the surrounding vehicles and a V2I signal reception
time t1-3 of the ego vehicle 9040, which are received by the ego
vehicle 9040.
= + t r .times. s .times. u - R .times. v .times. 1 d .times. i
.times. s .times. t + .alpha. R .times. v .times. 1 .times. .times.
= + t r .times. s .times. u - R .times. v .times. 2 d .times. i
.times. s .times. t + .alpha. R .times. v .times. 2 .times. .times.
= + t r .times. s .times. u - E .times. v d .times. i .times. s
.times. t + .alpha. E .times. v [ Equation .times. .times. 5 ]
##EQU00004##
[0113] In Equation 5, indicates the time when the RV1 vehicle 9020
received the signal of the RSU 9010, indicates the time when the
RV2 vehicle 9030 receives the signal of the RSU 9010, and indicates
the time when the ego vehicle 9040 receives the signal of the RSU
9010. indicates the time when the RSU 9010 transmits the signal.
t.sub.rsu-Rv1.sup.dist indicates a signal delivery time (may also
be denoted as a signal distance or a signal arrival distance in the
present disclosure) according to a distance between the RSU 9010
and the RV1 vehicle 9020. t.sub.rsu-RV2.sup.dist indicates a signal
delivery time according to the distance between the RSU 9010 and
the RV2 vehicle 9030. t.sub.rsu-EV.sup.dist indicates a signal
delivery time according to the distance between the RSU 9010 and
the ego vehicle 9040. .alpha..sub.Rv1, .alpha..sub.RV2, and
.alpha..sub.Ev indicate time synchronization errors of the RV1
vehicle 9020, the RV2 vehicle 9030, and the ego vehicle 9040,
respectively.
[0114] Referring to Equation 5, each of the V2I signal reception
time of a surrounding vehicle received by the ego vehicle 9040 and
the time when the ego vehicle 9040 actually receives the V2I signal
may include an error attributable to the time set in each
vehicle.
[0115] As described above, if a difference between V2I message
reception times is calculated using a value including an error, the
difference may have a non-zero value because it includes a time
synchronization error as in Equation 6.
.DELTA. RV .times. .times. 1 - EV = - = .alpha. RV .times. .times.
1 - .alpha. EV .noteq. 0 .times. .times. .DELTA. RV .times. .times.
2 - EV = - = .alpha. RV .times. .times. 2 - .alpha. EV .noteq. 0 [
Equation .times. .times. 6 ] ##EQU00005##
[0116] In Equation 6, .DELTA..sub.RV1-EV indicates a difference
between times when the RV1 vehicle 9020 and the ego vehicle 9040
received the V2I message, and .DELTA..sub.RV2-EV indicates a
difference between times when the RV2 vehicle 9030 and the ego
vehicle 9040 received the V2I message. Furthermore, t.sub.1-1,
t.sub.1-2, and t.sub.1-3 indicate the times when the RV1 vehicle
9020, the RV2 vehicle 9030, and the ego vehicle 9040 received the
signal transmitted by the RSU 9010, respectively.
[0117] Referring to Equation 5, it can be seen that an error is
included in a position measurement value if synchronization is not
performed between the vehicles.
[0118] Referring to FIG. 10, it may be seen that an erroneous
position 10050 of an RSU, such as that illustrated in FIG. 10, is
obtained if the position of the RSU is calculated with a time
synchronization error included as described above. Practically, an
RSU 10010 is present at the same distance as surrounding vehicles
as in the above assumption, but an ego vehicle 10040 has delta
values of non-zero (.alpha._RV1)-(.alpha._EV) and
(.alpha._RV2-.alpha._EV) values each indicative of a difference
between times when the signal (i.e., the V2I message) was received
due to time synchronization. If a hyperbola obtained accordingly is
used, a problem in that the position of the RSU is erroneously
estimated as a different position 10050 as illustrated in FIG. 10
may occur.
[0119] Accordingly, the present disclosure proposes a method of
removing an error attributable to time synchronization in the
proposed method of obtaining the position of a vehicle by using one
RSU.
[0120] FIG. 11 is a diagram for describing a method of obtaining a
relative position of an RSU according to an embodiment of the
present disclosure.
[0121] In an embodiment of the present disclosure, each of
surrounding vehicles may measure the time when a V2I message is
received using a time set in its vehicle, and may notify an
interval (or difference) between the time when the V2I message is
received and the time when its signal (e.g., a CAM or CPM message)
is transmitted, instead of the measured reception time. That is, a
V2X message transmitted by the surrounding vehicle may include
information on the interval (or difference) between the time when
the V2I message is received and the time when the V2X message is
transmitted.
[0122] Referring to FIG. 11, a case where distances from an RSU
11010 to surrounding vehicles (i.e., an RV1 vehicle 11020, an RV2
vehicle 11030, and an ego vehicle 11040 (or a current vehicle)) are
the same is assumed. Furthermore, a case where time of the RV1
vehicle 11020 is ahead of a reference time (i.e., time of the RSU
11010) by .alpha._RV1, time of the RV2 vehicle 11030 is behind the
reference time by .alpha._RV2, and time of the ego vehicle (or the
current vehicle) 11040 is ahead of the reference time by .alpha._EV
is assumed.
[0123] Each of the RV1 vehicle 11020 and the RV2 vehicle 11030 may
transmit a message including an interval (or difference) between
the time when the V2I message is received and the time when its
signal (e.g., a CAM or CPM message) is transmitted as in Equation
7.
t RV .times. .times. 1 p .times. r .times. o .times. c .times. e
.times. s .times. s = - = t 2 + .alpha. RV .times. .times. 1 - ( t
1 - 1 + .alpha. RV .times. .times. 1 ) = t 2 - t 1 - 1 .times.
.times. t RV .times. .times. 2 p .times. r .times. o .times. c
.times. e .times. s .times. s = - = t 3 + .alpha. RV .times.
.times. 2 - ( t 1 - 2 + .alpha. RV .times. .times. 2 ) = t 3 - t 1
- 2 [ Equation .times. .times. 7 ] ##EQU00006##
[0124] In Equation 7, t.sub.RV1.sup.process indicates a processing
time indicative of a difference between the time when the RV1
vehicle 11020 received the signal from the RSU 11010 and the time
when the RV1 vehicle 11020 transmits the signal, and
t.sub.RV2.sup.process indicates a processing time indicative of a
difference between the time when the RV2 vehicle 11030 received the
signal from the RSU 11010 and the time when the RV2 vehicle 11030
transmits the signal.
[0125] Referring to Equation 7, each of the RV1 vehicle 11020 and
the RV2 vehicle 11030 may calculate (or measure) a time difference
between the V2I signal reception time and the V2X signal
transmission time. Each of the time difference measured as
described above may be delivered to the ego vehicle 11040 through a
V2X message. The signals are used along with a value measured
through the timer of the ego vehicle 11040, and thus may have the
same time error (i.e., .alpha._EV). This may be represented as in
Equation 8 below.
= t 1 - 3 + .alpha. EV = t 1 + t rsu - EV dist + .alpha. EV .times.
.times. t 1 - 1 _ _ = t 2 - 2 + .alpha. EV - ( t Hv .times. .times.
1 process + t rsu - Hv .times. .times. 1 dist ) = t 1 + t rsu - RV
.times. .times. 1 dist + .alpha. EV .times. .times. t 1 - 2 _ _ = t
3 - 2 + .alpha. EV - ( t Hv .times. .times. 2 process + t rsu - Hv
.times. .times. 2 dist ) = t 1 + t rsu - RV .times. .times. 2 dist
+ .alpha. EV [ Equation .times. .times. 8 ] ##EQU00007##
[0126] Referring to Equation 8, a time t1-3 when the ego vehicle
11040 received the V2I signal may be calculated by summing the time
when the RSU 1101 transmits the V2I signal, a signal arrival time
from the RSU 1101 to the ego vehicle 11040, and the time error
.alpha._EV of the ego vehicle 11040. A time t.sub.1-1 when the RV1
vehicle 11020 received the V2I signal may be calculated (estimated)
by summing the time when the RSU 1101 transmits the V2I signal, a
signal arrival time from the RSU 1101 to the RV1 vehicle 11020, and
the time error .alpha._EV of the ego vehicle 11040. Furthermore, a
time t.sub.1-2 when the RV2 vehicle 11030 received the V2I signal
may be calculated (estimated) by summing the time when the RSU 1101
transmits the V2I signal, a signal arrival time from the RSU 1101
to the RV2 vehicle 11030, and the time error .alpha._EV of the ego
vehicle 11040.
[0127] Thereafter, a V2I signal reception time difference may be
calculated using the values calculated using Equation 8. In this
case, Equation 9 below may be used. In this case, the time error of
the ego vehicle 11040 may be removed.
.DELTA. RV .times. .times. 1 - EV = t 1 - 1 _ _ - = t rsu - RV
.times. .times. 1 dist - t rsu - EV dist .times. .times. .DELTA. RV
.times. .times. 2 - EV = t 1 - 2 _ _ - = t rsu - RV .times. .times.
2 dist - t rsu - EV dist [ Equation .times. .times. 9 ]
##EQU00008##
[0128] As an embodiment, each of the surrounding vehicles may
transmit the processing time (i.e., t.sub.Hv1.sup.process,
t.sub.Hv2.sup.process in Equation 7) indicative of a time
difference between the time when the V2I signal was received and
the time when the V2X signal is transmitted. The current vehicle
that received the processing times from the surrounding vehicle may
measure the time (i.e., in Equation 8) when the V2I signal was
received from the RSU and the times (i.e., and in Equation 8) when
the V2X signals were received from the surrounding vehicles.
Furthermore, the current vehicle may measure the distances (i.e.,
t.sub.rsu-RV1.sup.dist and t.sub.rsu-RV2.sup.dist in Equation 9)
between the current vehicle and the surrounding vehicles by using a
sensor mounted on the current vehicle. For example, the sensor may
be an ADAS sensor.
[0129] According to an embodiment of the present disclosure, even
in an environment in which time synchronization is not performed,
the position of a vehicle can be accurately obtained using an RSU
and surrounding vehicles. In other words, according to an
embodiment of the present disclosure, an error occurring because
time synchronization is not performed can be perfectly solved by
transmitting information on a time difference between the reception
of a V2I signal and the transmission of a V2X signal.
[0130] The method of measuring the position of a vehicle by using
only one RSU by considering a substantial vehicle operation
environment has been described above. Hereinafter, message
components for applying the method proposed in the present
disclosure is proposed. As an embodiment, the format of a message
transmitted by an RSU, the format of a message transmitted by the
existing CAM vehicle not having a sensor function, and the format
of a message transmitted by a CPS vehicle having a sensor function
are described. A V2X vehicle may transmit a CAM message or a CPM
message in order to periodically notify surroundings of information
as described above. In this case, a case where a vehicle having a
sensor function transmits a CPM message is basically described, but
the present disclosure is not limited thereto. A vehicle having a
sensor function may also transmit a CAM message and/or a CPM
message.
[0131] FIG. 12 is a diagram illustrating the structure of a data
frame of a V2I message transmitted by a road side unit (RSU)
according to an embodiment of the present disclosure.
[0132] Referring to FIG. 12, for the one-RSU positioning technology
(i.e., a position information acquisition technology using one RUS)
proposed in the present disclosure, a V2I message (or may also be
denoted as an 12V message or an RSU message) may include a
positioning RSU data frame. Specifically, DF_positioning_RSU may
include "PositioningFlag", "PositoningSeq", "FlagInterval" and/or
"Position" fields (or parameters or data elements).
[0133] The PositioningFlag field may be indicated using a Boolean
method. If a V2I signal (i.e., V2I message) is a signal that
requires a positioning operation, a corresponding flag value may be
set as "ture." The PositoningSeq field may be set (or defined) as
an integer, and may be used for the synchronization for the
transmission and reception of positioning signals through a
corresponding value. The Flag Interval field may be set as an
integer, and indicates a time period (or a time interval) in which
a Positioning Flag is transmitted. Accordingly, a receiver may
predict a period. Furthermore, the Position field may include
information on a fixed position of the RSU. For example, the
Position field may use DF_3DPosition, and may be defined as
OPTIONAL. If a Position value was transmitted in a previous
message, the Position field may not be included. If a Position
value was not transmitted in a previous message, the Position field
may be included. The DF_positioning_RSU data frame proposed in FIG.
12 may be added to (or included in) a V2I message (e.g., a CAM,
MAP, SPAT message).
[0134] FIG. 13 is a diagram illustrating the structure of a data
frame of a cooperative awareness message (CAM) according to an
embodiment of the present disclosure.
[0135] Referring to FIG. 13, for the one-RSU positioning technology
(i.e., the position information acquisition technology using one
RUS) proposed in the present disclosure, a CAM message may include
a positioning CAM data frame, such as that illustrated in FIG. 13.
Specifically, DF_positioning_CAM may include "PositioningSeq",
"TimeProcessing", and "Position" fields (or parameters or data
elements).
[0136] The PositoningSeq field may be set (or defined) as an
integer, and may be used for synchronization for the transmission
and reception of positioning signals. As an embodiment, when the
processing time described above with reference to FIG. 11 is
calculated, a PositioningSeq value of the V2I message may be
inserted. The TimeProcessing field may be set (or defined) as an
integer, and includes processing time information from the time
when a V2I message was received to the time when a CAM message is
transmitted. The Position field indicates its own position of a
vehicle that transmits the CAM message, may use DF_3DPosition, and
may be defined as OPTIONAL. The DF_positioning_CAM data frame
proposed in FIG. 13 may be added to (or included in) the CAM
message.
[0137] FIG. 14 is a diagram illustrating the structure of a data
frame of a collective perception message (CPS) according to an
embodiment of the present disclosure.
[0138] Referring to FIG. 14, for the one-RSU positioning technology
(i.e., the position information acquisition technology using one
RUS) proposed in the present disclosure, the CPM message may
include a positioning CPM data frame, such as that illustrated in
FIG. 14. Specifically, DF_positioning_CPM may include
"PositioningSeq", "TimeProcessing", and "Position" fields (or
parameters or data elements).
[0139] PositoningSeq may be set (or defined) an integer, and may be
used for synchronization for the transmission and reception of
positioning signals. As an embodiment, when the processing time
described above with reference to FIG. 11 is calculated, a
PositioningSeq value of the V2I message may be inserted. The
TimeProcessing field may be set (or defined) as an integer, and
includes processing time information from the time when the V2I
message was received to the time when the CAM message is
transmitted. The Position field indicates its own position of a
vehicle that transmits the CAM message, may use DF_3DPosition, and
may be defined as OPTIONAL.
[0140] Furthermore, a vehicle may transmit, to surrounding
vehicles, time propagation (TimePropagation) information for each
object through the CPM message. In this case, the time propagation
information indicates information that represents, as a signal
delivery distance time, the distance between each object and the
vehicle that transmits the CPM message. Specifically, in order to
transmit time propagation (TimePropagation) information for each
object, the CPM message may include ObjectID and/or TimePropagation
fields (or parameters or data elements), and each value thereof may
be defined as a sequence.
[0141] The ObjectID field indicates the ID of an object for
identifying the object, and may be defined as an integer. The
ObjectID field may use MessageID transmitted by each object. The
TimePropagation field represents, as a time, the distance between
each object and a vehicle that provides a CP service, and may be
defined as an integer. A CorrectedPositon field indicates its own
position of a vehicle that transmits a CPM message, and may use
DF_3DPosition. The CorrectedPositon field may include its own
accurate position information obtained using the method proposed in
the present disclosure. The positioning CPM data frame proposed in
FIG. 13 may be added to (or included in) the CPM.
[0142] The algorithms and message structures for the one-RSU
positioning technology (i.e., the position information acquisition
technology using one RUS) have been described above. Hereinafter, a
method of operating a message is described.
[0143] FIG. 15 is a flowchart illustrating a procedure of obtaining
and propagating position information of a vehicle that provides a
CP service according to an embodiment of the present
disclosure.
[0144] Referring to FIG. 15, an RSU 15010 may transmit, to
surrounding vehicles, a V2I message (or a V2I signal, an RSU
signal, an RSU message, an 12V signal or an 12V message) including
the Positioning V2I data frame described with reference to FIG. 11.
The surrounding vehicles that received the V2I message from the RSU
15010 may measure the time when the V2I message was received. A
vehicle that transmits a CAM may calculate a processing time
indicative of a time interval between the time when the V2I message
was received and the time when the CAM is transmitted, and may
transmit the processing time. A vehicle that transmits a CPM may
calculate a processing time indicative of a time interval between
the time when the V2I message was received and the time when the
CPM is transmitted, and may transmit the processing time.
Furthermore, the vehicle may transmit information on detected time
distances between objects through the CPM.
[0145] When receiving a V2I message whose positioning flag is on,
an ego vehicle (or a current vehicle) 15020 that provides a CP
service first measures the time when the V2I message was received.
Thereafter, the ego vehicle receives the CAMs from the surrounding
vehicles 15030 and 15040. In this case, the CAM may include
processing time information from the time when the V2I message was
received and the time when the CAM message is transmitted. In the
present embodiment, a case where the surrounding vehicles 15030 and
15040 transmit the CAMs is assumed, but the present disclosure is
not limited thereto. The surrounding vehicles may transmit CPMs,
and the CPMs may identically include the processing time
information.
[0146] When receiving two or more processing times from the
surrounding vehicles 15030 and 15040, the ego vehicle 15020
measures distances from the vehicles that transmitted the CAMs by
using a sensor mounted on the vehicle. Furthermore, the ego vehicle
15020 calculates a relative distance (or position) of the RSU by
using the processing times received from the surrounding vehicles
15030 and 15040 and the distance times measured when the CAMs were
received. Thereafter, the ego vehicle 15020 may calculate (or
estimate) its absolute position by using an absolute position value
of the RSU. The ego vehicle 15020 may transmit calculated position
information to the surrounding vehicles. As an embodiment, the CPM
transmitted by the ego vehicle 15020 may include the calculated
position information.
[0147] FIG. 16 is a flowchart illustrating a procedure of obtaining
and propagating position information of a vehicle that provides a
CA service according to an embodiment of the present
disclosure.
[0148] Referring to FIG. 16, a case where an ego vehicle (or a
current vehicle) 16020 transmits a CAM is assumed. Descriptions of
FIG. 16 that overlap those of FIG. 15 are omitted.
[0149] When receiving a V2I message whose positioning flag is on,
the ego vehicle (or current vehicle) 16020 that provides a CA
service first measures the time when the V2I message is received.
Thereafter, the ego vehicle receives CPMs from surrounding vehicles
16030 and 16040. In this case, the CPM may include processing time
information from the time when the V2I message was received to the
time when the CPM message is transmitted. In the present
embodiment, a case where the surrounding vehicles 16030 and 16040
transmit the CPMs is assumed, but the present disclosure is not
limited thereto. The surrounding vehicles may transmit CAMs, and
the CPMs may identically include the processing time
information.
[0150] When receiving two or more processing times from the
surrounding vehicles 16030 and 16040, the ego vehicle 16020
measures a distance from the vehicle that transmitted the CAM by
using a sensor mounted on the vehicle. Furthermore, the ego vehicle
16020 calculates a relative distance (or position) of an RSU by
using the processing times received from the surrounding vehicles
16030 and 16040 and distance times measured when the CAMs were
received. Thereafter, the ego vehicle 16020 may calculate (or
estimate) its absolute position by using an absolute position value
of the RSU. The ego vehicle 16020 may transmit the calculated
position information to the surrounding vehicles.
[0151] FIG. 17 is a diagram for describing a form in which a V2I
message is transmitted according to an embodiment of the present
disclosure.
[0152] Referring to FIG. 17, an RSU may transmit a V2I message in a
low period (e.g., 1 Hz). In this case, prior to a specific message,
the positioning RSU data frame described with reference to FIG. 12
may be inserted, and a positioning flag may be set as on. The RSU
may transmit the V2I message including a positioning flag set as on
in a preset specific period. For example, the aforementioned
specific period may be 10 seconds as illustrated in FIG. 17.
Furthermore, a repeated positioning flag may have a different
sequence every period.
[0153] In an embodiment, when receiving a V2I message including a
positioning flag, a vehicle that provides a CA service or a CP
service may measure the time when the V2I message was received as
described above, and may then transmit its message including
obtained position information. A transceiver that performs a
one-RSU positioning operation (i.e., an operation of obtaining
position information using one RUS) may identify its position while
exchanging messages in a given period.
[0154] FIG. 18 is a flowchart illustrating a method of generating a
V2I message according to an embodiment of the present
disclosure.
[0155] Referring to FIG. 18, when a V2I service system starts, an
RSU initializes the system and updates service content for
generating a V2I message (S18010, S18020).
[0156] When a positioning mode is turned off (i.e., off), the RSU
may generate the same V2I message as the existing message (S18070),
may generate a packet through a networks & transport layer and
an access layer, and may transmit the packet to surrounding
vehicles (S18080, S18090).
[0157] When the positioning mode is turned on, the RSU generates
DF_PositioningRSU (S18040). The RSU initializes a counter and
updates a sequence (S18050, S18060). The RSU may generate the
DF_PositioningRSU (S18070), may generate a packet through the
networks & transport layer and the access layer, and may
transmit the packet to the surrounding vehicles (S18080,
S18090).
[0158] FIG. 19 is a flowchart illustrating a method of generating a
CAM message according to an embodiment of the present
disclosure.
[0159] Referring to FIG. 19, when a CA service system starts, a V2X
vehicle initializes the system and receives a positioning flag
(PositioningFlag) from an RSU (S19010, S19020). When a positioning
flag is on, before transmitting a CAM, the V2X vehicle obtains the
time when a V2I message was received (S19040). Furthermore, the
vehicle calculates the aforementioned processing time based on the
time (S19050).
[0160] In an embodiment, a V2X vehicle to which a current vehicle
provides a CP service may measure the state and distance of an
object detected through a sensor, while calculating the processing
time.
[0161] The V2X vehicle generates a positioning CAM data frame based
on the processing time generated in step S19050, and generates a
CAM message including the positioning CAM data frame (S19060,
S19070). The V2X vehicle may generate a packet through a networks
& transport layer and an access layer, may generate a packet,
and may transmit the packet to surrounding vehicles (S19080,
S19090).
[0162] FIG. 20 is a flowchart illustrating a method of obtaining
position information according to an embodiment of the present
disclosure.
[0163] Referring to FIG. 20, when a system starts, a V2X vehicle
initializes an on board unit (OBU) system and waits to receive a
V2X message (S20010, S20020). When receiving the V2I message
(S20030), the V2X vehicle decodes the V2X message (S20040). If the
V2I message is a V2I message transmitted by an RSU, the V2X vehicle
checks a positioning flag (PositioningFlag) (S20060). When the
positioning flag is on, the V2X vehicle measures and stores a V2I
reception time (S20070). Furthermore, the V2X vehicle obtains an
absolute position of the RSU from the V2I message (S20080). The V2X
vehicle delivers, to the transmitter side, information obtained in
a previous step so that a positioning CAM data frame can be
generated (S20090). The V2X vehicle calculates the position of the
V2X vehicle by using the time when the V2I message was received and
the RSU position value (S20160).
[0164] When receiving a CPS message (S20100), the V2X vehicle
checks whether a CorrectedPosition value is included in the CPS
message (S20110). If the CorrectedPosition value is included in the
CPS message, the V2X vehicle may immediately recognize its absolute
position based on the CorrectedPosition value (S20160). If the
CorrectedPosition value is not included in the CPS message, the V2X
vehicle measures a CPM reception time, obtains values of a
processing time field and a propagation time field included in a
PositioningCPS data frame within the CPM (S20130), and stores
related parameters (S20140). When receiving two or more pieces of
CPS information, the V2X vehicle may calculate a relative position
of the RSU by applying the methods described with reference to
FIGS. 5 to 11 (S20150), and may estimate an actual position of the
V2X vehicle by comparing the relative position of the RSU and the
absolute position value of the RSU (S20160).
[0165] In an embodiment, the V2X vehicle may perform the same steps
S20100 to S20160 although it receives a CAM message.
[0166] FIG. 21 illustrates a configuration of a V2X communication
apparatus according to an embodiment of the present disclosure. As
described above, the V2X communication apparatus may also be
denoted as a V2X communication device, a V2X apparatus, etc.
[0167] In FIG. 21, the V2X communication apparatus 21000 may
include a communication unit 21010, a processor 21020, and a memory
21030.
[0168] The communication unit 21010 is connected to the processor
21020, and may transmit and receive radio signals. The
communication unit 21010 may up-convert, into a transmission and
reception band, data received from the processor 21020, and may
transmit a signal or may down-convert a received signal. The
communication unit 21010 may implement at least one operation among
a physical layer or an access layer.
[0169] The communication unit 21010 may include a plurality of
sub-RF units for communication according to a plurality of
communication protocols. As an embodiment, the communication unit
21010 may perform data communication based on ITS-G5 wireless
communication technologies based on the physical transmission
technologies of dedicated short range communication (DSRC), IEEE
802.11 and/or 802.11p standards, and IEEE 802.11 and/or 802.11p
standards, 2G/3G/4G(LTE)/5G wireless cellular communication
technologies including satellites/wideband wireless mobile
communication, wideband terrestrial digital broadcasting
technologies such as DVB-T/T2/ATSC, a GPS technology, an IEEE 1609
WAVE technology, etc. The communication unit 21010 may include a
plurality of transceivers that implement each communication
technology.
[0170] The processor 21020 is connected to the RF units 21010 and
may implement operations of layers of the V2X communication
apparatus. The processor 21020 may be configured to perform
operations according to various embodiments of the present
disclosure according to the aforementioned drawings and
description. Furthermore, at least one of a module, data, a
program, or software that implements operations of the V2X
communication apparatus 21000 according to the aforementioned
various embodiments of the present disclosure may be stored in the
memory 21030 and executed by the processor 21020.
[0171] The memory 21030 is connected to the processor 21020, and
stores various types of information for driving the processor
21020. The memory 21030 may be included within the processor 21020
or installed outside the processor 21020 and may be connected to
the processor 21020 by known means.
[0172] The processor 21020 of the V2X communication apparatus 21000
may perform the generation and transmission of an IPM described in
the present disclosure. A method of performing, by the V2X
communication apparatus 21000, V2X communication is described
below.
[0173] FIG. 22 is a flowchart illustrating a method of obtaining,
by a V2X communication apparatus, position information according to
an embodiment of the present disclosure.
[0174] Referring to FIG. 22, the V2X communication apparatus (or a
V2X vehicle) receives, from a road side unit (RSU), a V2I message
including position information of the RSU (S22010).
[0175] The V2X communication apparatus receives, from a first
surrounding vehicle and a second surrounding vehicle, the V2X
message including reception time information related to the time
when the V2I message was received (S22020). For example, the V2X
message may be a CAM or a CPM.
[0176] The V2X communication apparatus calculates a relative
position (or predicted position) of the RSU based on a current
vehicle, based on the reception time information and the time when
the current vehicle receives the V2I message (S22030).
[0177] The V2X communication apparatus obtains a position (i.e., an
absolute position or coordinates) of the current vehicle based on
the relative position of the RSU and the position information of
the RSU (S22040).
[0178] As an embodiment, the position information of the RSU may
include coordinates of the RSU. The position of the current vehicle
may be obtained by subtracting the relative position of the RSU
from the coordinates of the RSU. For example, in this case,
Equation 1 may be applied.
[0179] As an embodiment, the relative position of the RSU may be
calculated using a first difference value between the time when the
first surrounding vehicle received the V2I message and the time
when the current vehicle received the V2I message, and a second
difference value between the time when the second surrounding
vehicle received the V2I message and the time when the current
vehicle received the V2I message. In this case, the methods
described with reference to FIGS. 6 to 8, 11 and Equations 4, 7 to
9 may be applied.
[0180] As an embodiment, the reception time information may include
time interval (or processing time) information from the time when
the first surrounding vehicle or the second surrounding vehicle
received the V2I message to the time when the first surrounding
vehicle or the second surrounding vehicle transmits the V2X
message. For example, the method described with reference to FIG.
11 may be applied.
[0181] As an embodiment, the aforementioned position information of
the method may further include a step of generating a cooperative
awareness (CA) message or a collective perception (CP) message
including the obtained position of the current vehicle. In other
words, the V2X communication apparatus may transmit accurate
position information to the surrounding vehicles through the CAM or
CPM including the position information of the vehicle obtained by
applying the method proposed in the present disclosure.
[0182] In the aforementioned embodiments, the elements and
characteristics of the disclosure have been combined in a specific
form. Each of the elements or characteristics may be considered to
be optional unless otherwise described explicitly. Each of the
elements or characteristics may be implemented in a form to be not
combined with other elements or characteristics. Furthermore, some
of the elements and/or the characteristics may be combined to form
an embodiment of the disclosure. The sequence of the operations
described in the embodiments of the disclosure may be changed. Some
of the elements or characteristics of an embodiment may be included
in another embodiment or may be replaced with corresponding
elements or characteristics of another embodiment. It is evident
that an embodiment may be constructed by combining claims not
having an explicit citation relation in the claims or may be
included as a new claim by amendments after filing an
application.
[0183] The embodiment according to the disclosure may be
implemented by various means, for example, hardware, firmware,
software or a combination of them. In the case of an implementation
by hardware, the embodiment of the disclosure may be implemented
using one or more application-specific integrated circuits (ASICs),
digital signal processors (DSPs), digital signal processing devices
(DSPDs), programmable logic devices (PLDs), field programmable gate
arrays (FPGAs), processors, controllers, microcontrollers,
microprocessors, etc.
[0184] In the case of an implementation by firmware or software,
the embodiment of the disclosure may be implemented in the form of
a module, procedure or function for performing the aforementioned
functions or operations. Software code may be stored in the memory
and driven by the processor. The memory may be located inside or
outside the processor and may exchange data with the processor
through a variety of known means.
[0185] It is evident to those skilled in the art that the
disclosure may be materialized in other specific forms without
departing from the essential characteristics of the disclosure.
Accordingly, the detailed description should not be construed as
being limitative, but should be construed as being illustrative
from all aspects. The scope of the disclosure should be determined
by reasonable analysis of the attached claims, and all changes
within the equivalent range of the disclosure are included in the
scope of the disclosure.
MODE FOR INVENTION
[0186] Those skilled in the art will understand that the disclosure
may be changed and modified in various ways without departing from
the spirit or range of the disclosure. Accordingly, the disclosure
is intended to include all the changes and modifications provided
by the appended claims and equivalents thereof.
[0187] In this disclosure, both the apparatus and the method have
been described, and the descriptions of both the apparatus and
method may be complementarily applied.
[0188] Various embodiments have been described in the best form for
implementing the disclosure.
INDUSTRIAL APPLICABILITY
[0189] The disclosure is used in a series of V2X communication
fields.
[0190] Those skilled in the art will understand that the disclosure
may be changed and modified in various ways without departing from
the spirit or range of the disclosure. Accordingly, the disclosure
is intended to include all the changes and modifications provided
by the appended claims and equivalents thereof.
* * * * *